COLOR DOPPLER SONOGRAPHY OF THE RETROBULBAR ARTERIES IN NORMAL TENSION-ANGLE AND OPEN-ANGLE GLAUCOMA

Background. Various authors report that the glaucomatous loss of uncti on is due to a chronic anterior ischemic optic neuropathy, being cause d by a disturbed relationship between intraocular pressure and perfusi on pressure in the posterior short ciliary arteries, which possibly le ads to increased resistance in the ciliary vascular system. The author s attempt to test this hypothesis by measuring the vascular resistance (Resistance Index) in the ciliary vessel system by means of color Dop pler sonography. Patients and Methods. 35 eyes of 35 patients, sufferi ng from open angle glaucoma (OAG), with a mean age of 65,3 years, were examined as well as 35 eyes of 35 patients with normal tension glauco ma (NTG), whose mean age was 65,8 years. Both glaucoma groups were com pared to an age- and sex-matched control group of healthy volunteers. The color-Doppler measurements were performed with an Acuson 128 XP/10 , which allows imaging of all retrobulbar arteries: the ophthalmic art ery. the central retinal artery and the short posterior ciliary arteri es, and also guarantees the precise calculation of blood flow velocity and resistive index (RI). The RI was statistically evaluated. Results . The resistance index of all retrobulbar arteries showed a statistica lly significant increase (p < 0.05) according to Wilcoxon's test in th e OAG group as well as the NTG group. Conclusions. Increased vascular resistance was found in all retrobulbar arteries in OAG and in NTG. Th ese findings point out the pathognomonic importance of perfusion distu rbance in glaucoma.